HP 540b schematic
TM 11-6625-493-15
DEPARTMENT OF THE ARMY TECHNICAL MANUAL
DS, GS, AND DEPOT MAINTENANCE
MANUAL
FREQUENCY COMPARATOR
CM-77A/USM
This copy is a reprint which includes current
pages from Changes 1 through 4.
HEADQUARTERS, DEPARTMENT OF THE ARMY
SEPTEMBER 1964
Changes in force C1, C3, and C4
Operators, Organizational, Direct Support,
General Support, and Depot
Maintenance Manual
FREQUENCY COMPARATOR CM977A/USM
(NSN 6625-00-080-7204)
TM 11-6625-493-15, 29 September 1964, is changed as follows:
The title of the manual is changed as shown above.
Page v, The Forms and Records paragraph is
superseded as follows:
TM 11-6625-493-15
C4
HEADQUARTERS
DEPARTMENT OF THE ARMY
ASHINGTON , DC, 9 May 1977
W
0-1. Forms and Records
a. Reports of Maintenance and Unsatisfactory
Equipment. Maintenance forms, records, and reports
which are to be used by maintenance personnel at all
maintenance levels are listed in and prescribed by
TM 38-750.
b. Report of Packaging and Handling Deficien-
cies. Fill out and forward DD Form 6 (Packaging Im-
provement Report) as prescribed in AR 70058/NAVSUPINST 4030.29/AFR 71-13/MCO
P4030.29A, and DSAR 4145.8.
c. Discrepancy in Shipment Report (DISREP) (SF
361). Fill out and forward Discrepancy in Shipment
Report (DISREP) (SF 361) as prescribed in AR 5538/NAVSUPINST 4610.33A/AFR
4610.19B and DSAR 4500.15
The Reporting of Errors paragraph is superseded as
follows:
75-18/MCO
0-2. Reporting of Errors
You can help improve this manual by calling atten tion to errors and by recommending improve-
ments and stating your reasons for the recommendations. Your letter or DA Form 2028 (Recommended
Changes to Publications and Blank Forms) should be
mailed direct to Commander, US Army Electronics
Command, ATTN: DRSEL-MA-Q, Fort Monmouth,
New Jersey 07703. A reply will be furnished direct to
you. After the Reporting of Errors paragraph, add
the following:
0-3. Administrative Storage
Administrative storage of equipment issued to and
used by Army activities shall be in accordance with
TM 740-90-1.
0-4. Destruction of Army Electronics
Materiel.
Destruction of Army electronics materiel to prevent
enemy use shall be in accordance with TM
750-244-2.
0-5. Reporting Equipment improve-
ment Recommendations (EIR)
EIR’s will be prepared using DA Form 2407 (Maintenance Request). Instructions for preparing EIR’s are
provided in TM 38-750, The Army Maintenance
Management System. EIR’s should be mailed direct
to Commander, US Army Electronics Command,
ATTN: DRSEL-MA-Q, Fort Monmouth, New Jersey
07703. A reply will be furnished direct to you.
Page 5-2, Table 5-1 is superseded as follows:
1
Table 5-1. Test Equipment
Page 5.1-1. Section V.I is superseded as follows:
SECTION V.1
PREVENTIVE MAINTENANCE INSTRUCTIONS
5.1-1. Scope of Organizational
Preventive Maintenance
Preventive maintenance is the systematic care, servicing, and inspection of equipment to prevent the occurrence of trouble, to reduce downtime, and to
assure that the equipment is serviceable.
a. Systematic Care. The procedures given in
tables 5.1-1 and 5.1-2 cover routine systematic care
essential to proper upkeep and operation of the
equipment.
b. Preventive Maintenance Checks and Services.
The preventive maintenance checks and services
tables outline the functions to be performed at
specific intervals. These checks and services are
designed to maintain Army equipment in a combatserviceable condition; that is, in good physical and
operational condition. To assist organizational
maintenance personnel in maintaining combat serviceability, the table indicate what to check, how to
check, and the normal conditions. If the defect cannot be remedied by organizational maintenance personnel, higher category maintenance or repair is required. Records and reports of these checks and services must be made in accordance with TM 38-750.
5.1-2. Preventive Maintenance Checks
and Services Periods
Preventive maintenance checks and services of the
equipment is required on a daily, weekly, and
monthly basis as indicated in a and b below.
Whenever a normal indication is not observed during the performance of the daily, weekly, or monthly
preventive maintenance check, necessary corrective
action must be taken.
a. Daily and Weekly. Table 5.1-1 specifies the
preventive maintenance checks and services that
must be performed daily and weekly or when the
equipment is:
(1) Initially installed.
2
(2) Reinstalled after return from higher cate
gory of maintenance and repairs have been performed.
(3) Maintained in a standby (ready for immedi-
ate operation) condition. Perform on a monthly
schedule.
ly 30 calendar days of 8-hour-per-day operation. Ad-
justment of the monthly preventive maintenance in-
terval must be made to compensate for any unusual
operating conditions. For example, if the equipment
is used 16 hours per day, the monthly preventive
(4) Returned to service from limited storage. maintenance checks and services should be per-
b. Monthly. Table 5.1-2 specifies the preventive
maintenance checks and services that must be per-
formed monthly. A month is defined as approximatc-
formed at 15-day intervals. ACM-77A maintained in
a standby condition requires monthly preventive
maintenance, but one in limited storage does not.
Table 5.1-1. Daily and Weekly Preventive Maintenance Checks and Services
para 3-6
Table 5.1-2. Monthly Preventative Maintenance Checks and Services
para 5-4 and 5-5
5.1-3. Cleaning
Inspect the exterior of the equipment. The exterior
should be clean, and free from dust, dirt, grease, and
fungus.
a. Remove dust and loose dirt with a clean lint-
free cloth.
WARNING
The fumes of trichloroethane are toxic. Provide thorough ventilation whenever used.
paragraph 5-3
DO NOT USE NEAR AN OPEN FLAME.
Trichloroethane is not flammable, but exposure of the fumes to an open flame or hot
metal forms highly toxic phosgene gas.
b. Remove grease, fungus, and ground-in dirt
from the case; use a cloth dampened (not wet) with
trichloroethane. After cleaning, wipe dry with a
clean lint-free cloth.
c. Remove dust or dirt from plugs and jacks with
3
a soft-bristled brush.
CAUTION
Do not press on the face (glass) of the
cathode ray tube when cleaning; the cathode
ray tube may become damaged.
d. Clean the front panel and control knobs; use a
soft clean lint-free cloth. If necessary, dampen the
cloth with water. Mild soap may be used for more effective cleaning.
cloth .
Wipe dry with a clean lint-free
5.1-4. Paints and Finishes
When the CM-77A/USM requires repainting,
refinishing, or touchup painting, refer to Federal
Standard No. 595a for a matching color. SB 11-573
lists. painting tools and miscellaneous supplies required for painting.
5.1-5. Touchup Painting Instructions
a. Refer to TB 43-0118 for instructions on paint-
ing and preserving Electronics Command equip-
ment. When touchup painting, a perfect match with
the exact shade of the original paint surface may not
be possible. This may be caused by changes such as
in the original pigment because of oxidation, and differences in manufacture. The prevention of corrosion
and deterioration is the most important consideration in touchup painting; appearance is secondary.
This, however, should not be construed to mean that
appearance of the equipment is not important.
Touckup painting should be accomplished neatly
and the quality of work should be good. Field inspection personnel should make allowances for slight color mismatch where minor touchup has been done,
but not for neglect, poor quality, or where the need
for refinishing is obvious.
b. Remove rust and corrosion from metal surfaces
by lightly sanding them with fine sandpaper. Brush
two thin coats of paint on the bare metal to protect it
from further corrosion.
Page i-2. Appendix 1 is superseded as follows:
APPENDIX A
REFERENCES
The following is a list of references that are available to the operator and organizational, DS, GS, and
depot maintenance personnel of Frequency Comparator CM-77A/USM:
DA Pam 310-4
DA Pam 310-7
SB 11-573
TB 43-180
TB 43-0118
TM 11-6625-200-15
TM 11-6625-258-14
TM 11-6625-274-12
TM 11-6625-316-12
TM 11-6625-320-12
TM 11-6625-366-15
TM 11-6625-412-15-1
Index of Technical Manuals, Technical Bulletins, Supply Manuals (Types 7, 8 and
9), Supply Bulletins, and Lubrication Orders.
US Army Index of Modification Work Orders.
Painting and Preservation Supplies Available for Field Use for Electronics
Command Equipment.
Calibration Requirements for the Maintenance of Army Materiel.
Field Instructions for Painting and Preserving Electronics Command Equipment
Including Camouflage Pattern Painting of Electrical Equipment Shelters
Operator’s, Organizational,
Multimeters ME-26A/U, ME-26B/U, ME-26C/U, and ME-26D/U.
Operator’s, Organizational, Direct Support, and General Support Maintenance
Manual: Signal Generators SG-299/U, SG-299A/U, SG-299B/U, SG-299C/U,
SC-299D/U and SG-299E/U.
Operator’s and Organizational Maintenance Manual: Test Sets, Electron Tube
TV-7/U, TV-7A/U, TV-7B/U, and TV-7D/U.
Operator’s and Organizational Maintenance Manual: Test Sets, Electron Tube
TV-2/U, TV-2A/U, TV-2B/U, and TV-2C/U.
Operator’s and Organizational Maintenance Manual: Voltmeter, Meter
ME-30A/U and Voltmeters, Electronic ME-30B/U, ME-30C/U, and ME-30E/U.
Operator’s, Organizational, EM, CS, and Depot Maintenance Manual: Multimeter
TS-352B/U.
Operator, Organizational, DS, GS, and Depot Maintenance Manual,
Repair Parts and Special Tools List: Radio Test Set AN/URM-44A.
DS, GS, and Depot Maintenance Manual:
Including
4
TM 11-6625-700-14-1
TM 11-6625-1703-15
TM 38-750
TM 740-90-1
TM 750-244-2 Procedures for Destruction of Electronics Materiel to Prevent Enemy Use
Page i-3, Appendix II is superseded as follows:
Operator’s, Organizational, Direct Support, and General Support Maintenance
Manual Including Repair Parts and Special Tools List (Including Depot
Maintenance Repair Parts and Special Tools): Digital Readout Electronic
Counter AN/USM-207A (Serial Nos. 1A through 1100A).
Operator, Organizational, DS, GS, and Depot Maintenance Manual Including
Repair Parts and Special Tool Lists: Oscilloscope AN/USM-281A.
The Army Maintenance Management System (TAMMS).
Administrative Storage of Equipment
(Electronics Command).
APPENDIX C
MAINTENANCE ALLOCATION
Section I. INTRODUCTION
C-1. General
This appendix provides a summary of the
maintenance operations for CM-77A/USM. It authorizes categories of maintenance for specific maintenance functions on repairable items and components and the tools and equipment required to perform each function. This appendix may be used as an
aid in planning maintenance operations.
C-2. Maintenance Function
Maintenance functions will be limited to and defined
as follows:
a. Inspect. To determine the serviceability of an
item by comparing its physical, mechanical, and/or
electrical characteristics with established standards
through examination.
b. Test. To verify serviceability and to detect incipient failure by measuring the mechanical or electrical characteristics of an item and comparing those
characteristics with prescribed standards.
c. Service. operations required periodically to
keep an item in proper operating condition, i.e., to
clean (decontaminate), to preserve, to drain, to paint,
or to replenish fuel, lubricants, hydraulic fluids, or
compressed air supplies.
d. Adjust. To maintain, within prescribed limits,
by bringing into proper or exact position, or by setting the operating characteristics to the specified
parameters.
e. Align. To adjust specified variable elements of
an item to bring about optimum or desired performance.
f. Calibrate. To determine and cause corrections
to be made or to be adjusted on instruments or test
measuring and diagnostic equipments used in precision measurement. Consists of comparisons of two
instruments, one or which is a certified standard of
known accuracy, to detect and adjust any discrepancy in the accuracy of the instrument being compared.
g. Install. The act of emplacing, seating, or fixing
into position an item, part, module (component or
assembly) in a manner to allow the proper functioning of the equipment or system.
h. Replace. The act of substituting a serviceable
like type part, subassembly, or module (component
or assembly) for an unserviceable counterpart.
i. Repair. The application of maintenance serv-
ices (inspect, test, service, adjust, align, calibrate, re-
place) or other maintenance actions (welding, grind-
ing, riveting, straightening, facing, remachining, or
resurfacing) to restore serviceability to an item by
correcting specific damage, fault, malfunction, or
failure in a part, subassembly, module (component
or assembly), end item, or system. This function does
not include the trial and error replacement of run-
ning spare type items such as fuses, lamps, or elec-
tron tubes.
j. Overhaul. That maintenance effort (service/
action) necessary to restore an item to a completely
serviceable/operational condition as prescribed
by maintenance standards (i.e., DMWR) in appropriate technical publications. Overhaul is normally
the highest degree of maintenance performed by the
5
Army. Overhaul does not normally return an item to
like new condition.
k. Rebuild. Consists of those services/actions
necessary for the restoration of unserviceable equipment to a like new condition in accordance with
original manufacturing standards. Rebuild is the
highest degree of materiel maintenance applied to
Army equipment. The rebuild, operation includes the
act of returning to zero those age measurements
(hours, miles, etc.) considered in classifying Army
equipments/components.
C-3. Column Entries
a. Column 1, Group Number. Column 1 lists
group numbers, the purpose of which is to identify
components, assemblies, subassemblies, and modules
with the next higher assembly.
b. Column 2, Component/Assembly. Column 2
contains the noun names of components, assemblies,
subassemblies, and modules for which maintenance
is authorized.
c. Column 3, Maintenance Functions. Column 3
lists the functions to be performed on the item listed
in column 2. When items are listed without maintenance functions, it is solely for purpose of having the
group numbers in the MAC and RPSTL coincide.
d. Column 4, Maintenance Category. Column 4
specifies, by the listing of a “work time” figure in the
appropriate subcolumn(s), the lowest level of maintenance authorized to perform the function listed in
column 3. This figure represents the active time required to perform that maintenance function at the
indicated category of maintenance. If the number or
complexity of the tasks within the listed maintenance
function vary at different maintenance categories,
appropriate “work time” figures will be shown for
each category. The number of task-hours specified by
the “work time” figure represents the average time
required to restore an item (assembly, subassembly,
component, module, end item or system) to a service-
able condition under typical field operating conditions. This time includes preparation time, troubleshooting time, and quality assurance/quality control
time in addition to the time required to perform the
specific tasks identified for the maintenance func-
tions authorized in the maintenance allocation cha
Subcolumns of column 4 are as follows:
C - Operator/Crew
O - Organizational
F - Direct Support
H - General Support
D - Depot
e. Column 5, Tools and Equipment. Column
specifies by code, those common tool sets (not in
dividual tools) and special tools, test, and supper
equipment required to perform the designated func
tion.
f. Column 6, Remarks. Column 6 contains an al
phabetic code which leads to the remark in section
IV, Remarks, which is pertinent to the item opposite
the particular code.
C-4. Tool and Test Equipment
Requirements (Sect. Ill)
a. Tool or Test Equipment Reference Code. The
numbers in this column coincide with the numbers
used in the tools and equipment column of the MAC.
The numbers indicate the applicable tool or test
equipment for the maintenance functions.
b. Maintenance Category. The codes in this column indicate the maintenance category allocated the
tool or test equipment.
c. Nomenclature. This column lists the noun
name and nomenclature of the tools and test equipment required to perform the maintenance functions.
d. National/NATO Stock Number. This column
lists the National/NATO stock number of the specific
tool or test equipment.
e. Tool Number. This column lists the manufacturer’s part number of the tool followed by the
Federal Supply Code for manufacturers (5-digit) in
parentheses.
C-5. Remarks (Sect. IV)
a. Reference Code. This code refers to the appropriate item in section II, column 6.
b. Remarks. This column provides the required
explanatory information necessary to clarify items
appearing in section II.
6
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TW replacement 6f knobs, fuse, and leap.
RSMARKS
REMARKS
9
By Order of the Secretary of the Army:
Official:
PAUL T. SMITH
Major General, United States Army
The Adjutant General
Distribution:
Active Army
BERNARD W. ROGERS
General, United States Army
Chief of Staff
USASA (2)
COE (1)
TSG (1)
USAARENBD (1)
TECOM (2)
TRADOC (2)
OS Maj Comd (4)
USACC (4)
MDW (1)
Armies (2)
Corps (2)
Instl (2) except
Ft Gillem (10)
ARNG: State AC (3)
USAR: None
For explanation of abbreviations used, see AR310-50.
Ft Gordon (10)
Ft Huachuca (10)
Ft Carson (5)
SAAD (30)
LBAD (14)
TOAD (14)
SHAD (3)
HISA (Ft Monmouth) (33)
Ft Richardson (ECOM Ofc) (2)
Svc Colleges (1)
USASIGS (5)
USAICS (3)
USAADS (2)
USAFAS (2)
USAARMS (2)
USAIS (2)
USAES (2)
MAAG (1)
USARMIS (1)
USAERDAA (1)
USAERDAW (1)
Sig FLDMS (1)
Units org under fol TOE:-1 ea
11-500(AA-AC)
29-134
29-136
THIS MANUAL CONTAINS INFORMATION COPYRIGHTED BY
HEWLETT-PACKARD COMPANY.
TM 11-6625-493-15
TECHNICAL MANUAL )
NO. 11-6625-493-15 )
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section
I
II
III
GENERAL INFORMATION
1-1.
1-9. Differences in Instruments . . . . . . . . . . . . . . . . .
INSTALLATION
2-1.
2-3. Repacking for Shipment . . . . . . . . . . . . . . . . . . . . . .
2-5.
2-7. Operation from 115- or 230-Volt Line . . . . . . . . . . . . . . . . . . . .
2-10. Operation on Line Frequencies Higher than 120 Cycles
2-12. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OPERATING INSTRUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1.
3-3.
3-9.
3-12.
3-14.
3-16.
3-18.
3-26.
3-28.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . .
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . .
Power Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Measuring Frequency . . . . . . . . . . . . . . . . . . . . . .
Measuring Fm Carrier Frequency and Limits of Frequency
Measuring Pulsed Rf Signals
Use of Frequency Control Connector . . . . . . . . . . . . . . . . . . . . . .
Extending the Operating Range from 12.4 Gc to 18 Gc . . . . .
Measuring Detailed Characteristics of Fm Signals . . . . . . . .
Generating Harmonics for Other Uses . . . . . . . . . . . . . . . . . . . . .
Measuring frequencies above 18 Gc . . . . . . . . . . . . . . . . .
)
Washington, D.C. 29 September 1964
DS, GS, and Depot Maintenance Manual
Frequency Comparator CM-77A/USM
. . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Per Second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . .
HEADQUARTERS,
DEPARTMENT OF THE ARMY
Page
v
1-1
1-1
1-1
2-1
2-1
2-1
2-1
2-1
2-1
2-1
3-1
3-1
3-1
3-8
3-8
3-11
3-11
3-12
3-14
3-14
IV
V
THEORY OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-1. Circuit Description . . . . . . . . . . . . . . . . . . . . . . .
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-1.
5-7.
5-9.
5-11.
5-13.
5-19.
5-21.
5-23.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-3.
Cabinet Removal . . . . . . . . . . . . . . . . . . . . . . . . . .
5-5.
Periodic Cleaning and Lubrication . . . . . . . . . . . . . . . .
Tube Replacement . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply Test and Adjustment . . . . . . . . . . . . . . . . .
Testing Oscillator Output and Dial Calibration . . . . . . . . . .
Measuring Video Amplifier Gain and Response . . . . . . . . . . . . .
Centering Oscilloscope Trace . . . . . . . . . . . . . . . . . . .
4-1
4-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-3
5-4
5-5
i
Section
Page
5-25.
5-27.
5-30.
5-35.
V.1
VI
APPENDIX I. REFERENCES
PREVENTIVE MAINTENANCE INSTRUCTIONS
5.1-1.
5.1-2.
5.1-3.
5.1-4.
5.1-5.
5.1-6.
5.1-7.
5.1-8.
5.1-9.
REPLACEABLE PARTS
6-1.
Measuring Mixer Sensitivity and Frequency Response . . . . . .
Replacing Parts in the Low Frequency Mixer . . . . . . . . . . . . . . 5-6
Replacing Parts in the High Frequency Mixer . . . . . . . . . . . . . 5-6
Harmonic Generator Assembly . . . . . . . . . . . . . . . . . . . . . . 5-7
Scope of Maintenance . . . . . . . . . . . . . . . . .... . . . . . . . .
Preventive Maintenance .. . . . . . . . . . . . . . . . . . . . . . . . .
Preventive Maintenance Checks and Services Periods . . . . .
Daily Preventive Maintenance Checks and Services
chart
Weekly Preventive Maintenance Checks and Services
chart
Monthly Preventive Maintenance Checks and Services
chart
Quarterly Preventive Maintenance Checks and
Services Chart
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Touchup Painting Instructions . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
II. MAINTENANCE ALLOCATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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5-5
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.5.1-1
5.1-1
5.1-1
5.1-1
5.1-3
5.1-4
5.1-5
5.1-6
5.1-7
5.1-7
6-1
i-2
i-3
ii
Model 540B
List of Illustrations
List of Tables
LIST OF ILLUSTRATIONS
Figure
Model 540B, Front View . . . . . . . . . 1-1
1-1.
1-2.
Diagram of Panel Connections and
Functional Groups . . . . . . . . . . . . 1-3
Power Transformer Primary Winding . 2-1
2-1.
Measuring CW and FM Signals . . . . 3-0
3-1.
Typical Mixer Input Sensitivity . .. 3-1
3-2.
3-3.
Controls, Indicators and Connectors . . 3-2
Typical Sequence of Oscilloscope Patterns
3-4.
Obtained as Difference Frequency is
Reduced to Zero, with a Stable CS
Input Signal . . . . . . . . . . . . . . . 3-4
Typical Oscilloscope Patterns Obtained
3-5.
when CW Input Signal has some
Frequency Deviation . . . . . . . . . . . 3-4
Nomograph for Determining a Harmonic
3-6.
Number of an Unknown Frequency Between
400 MC and 2 GC from Two Adjacent
Frequencies Obtained with the 540B. . 3-6
Nomograph for Determining a Harmonic
3-7.
Number of Unknown Frequency Between
2 and 5 GC from Two Adjacent Fre-
quencies Obtained withthe 540B . . . . . 3-7
Typical Oscilloscope Patterns Obtained
3-8.
when Input Signal is Frequency-
Modulated . . . . . . . . . . . . . . . . 3-8
Measuring Pulse-Modulated RF Signals. 3-9
3-9.
Typical Patterns Obtained on External
3-10.
Synchronized Oscilloscope, when meas-
ing Pulse-Modulated RF Signals . . . . . 3-10
Page
Figure
Typical Patterns Obtained on External
3-11.
3-12.
3-13.
3-14.
3-15.
3-16.
4-1.
Synchronized Oscilloscope when the
Pulse Presentations of Figure 3-10
are Differentiated at the Oscilloscope
Input . . . . . . . . . . . . . . . . . . . . .
Effect of Resistance Connected Across
FREQUENCY CONTROL Connector. .
Effect of Voltage Connected Across
FREQUENCY CONTROL Connector .
Making Measurements at Frequencies
between 12.4 and 18 GC . . . . . . . . . .
System To Measure Frequency Modu-
lation Characteristics . . . . . . . . . .
Design Information for a Simple
Three-Section Low -Pass Filter . . . .
Transfer Oscillator Block Diagram . .
Location of Measurement and Adjust-
5-1.
ment Points . . . . . . . . . . ..
Waveform Definitions . . . . . . . . . . .
5-2.
Low Frequency Harmonic Mixer . . . .
5-3.
High Frequency Harmonic Mixer . . . .
5-4.
Harmonic Generator . . . . . . . . . . . .
5-5.
Oscillator Assembly . . . . . . . . . . . .
5-6.
Chassis Board, Parts Location . . . .
5-7.
Resistor Board, Parts Location . . . .
5-8.
Voltage and Resistance Diagram . . . .
5-9.
Power Supply, Schematic Diagram. . .
5-10.
Oscillator, Schematic Diagram . . . . .
5-11.
Page
.. 3-10
.. 3-11
.. 3-11
.. 3-12
.. 3-13
.. 3-15
.. 4-1
. . 5-3
. . 5-5
. . 5-6
. . 5-6
. . 5-7
. . 5-8
. .
5-9
. . 5-10
. . 5-11
. .
5-12
5-13
LIST OF TABLES
Number
1-1. Specifications . . . . . . . . . . . . . . .1-2
3-1. Function of Controls, Indicators, and
5-1.
5-2.
5-3. Trouble Localization . . . . . . . . . . 5-5
6-1. Reference Designator . . . . , . . . 6-2
6-2. Replaceable Parts . . . . . . . . . .6-7
Connectors . . . . . . . . . . . . 3-2
Test Equipment . . . . . . . . . . 5-2
Adjustments Required when Tubes
are Replaced . . . . . . . . . . . . . . .5-4
Page
iii
Section I
Figure 1-1
Model 540B
iv
Figure 1-1. Model 540B, Front View
TM 11-6625-493-15
FOREWORD
Cl
Throughout this manual, reference is made to Model 540B Transfer
oscillator which is a commercial designation and is identical with Frequency
comparator CM-77A/USM. This is a first-edition manual containing preliminary
and unreviewed information compiled by the manufacturer of the equipment.
Judicious caution should be exercised in using the information in this
manual until it is replaced by a revised edition.
Index of Equipment Publications
Refer to the latest issue of DA Pam 31C-4 to determine whether there are
new editions, changes, or additional publications pertaining to the
equipment. Department of the Army Pamphlet No. 310-4 is an index of current
technical manuals, technical bulletins, supply manuals, supply bulletins,
lubrication orders, and modification work orders available through publications supply channels. The index lists the individual parts (-10, -20, -35P,
etc) and the latest changes to and revisions of each equipment publication.
Forms and Records
Reports of Maintenance and Unsatisfactory Equipment. Use equipment
forms and records in accordance with instructions in TM 38-750.
Report of Damaged or Improper Shipment. Fill out and forward DDForm 6
(Report of Damaged or Improper Shipment) as prescribed in AR 700-58 (Army),
NAVSANDA Publication 378 (Navy), and AFR 71-4 (Air Force).
Reporting of Equipment Manual Improvements. The direct reporting, by
the individual user, of errors, omissions, and recommendations for
improving this equipment manual is authorized and encouraged. DA Form 2028
till be used for reporting these improvements. This form may be completed
by using pencil, pen, or typewriter.
triplicate and forwarded by the individual using the manual.
DA Form 2028 will be completed in
The original
and one copy will be forwarded direct to: Commanding General, U. S. Army
Electronics Command, ATTN: AMSEL-MR-(NMP)-MA,
Fort Monnouth, New Jersey
07703.
v
Model 540B Section I
Paragraphs 1-1 to 1-10
SECTION I
GENERAL INFORMATION
1-1. INTRODUCTION.
1-2.
PURPOSE AND USE. The Hewlett - Packard
Model 540B Transfer Oscillator is an electronic frequency-measuring instrument which, extends the frequency measurement range of the Hewlett - Packard
524 and 5243 series of electronic frequency counters
into the microwave region. The transfer oscillator frequency counter combination measure frequencies
up to 12.4 gigacycles (gc), or with an external mixer,
up to 18 gc, with near-counter accuracy. The Model
540B can also be used without a frequency counter to
measure frequency below 4 gc within about ± 1/2%.
1-3. The method used in the Model 540B Transfer
Oscillator to determine frequency is to zero-beat the
unknown input signal with a harmonic of an extremelystable signal generated in the 540B, and to measure
the 540B fundamental frequency on a counter. Multi-
plying the counter readout by the number of the har-
monic causing the zero-beat gives the input signal frequency. The harmonic number is determined either
from previous knowledge of the input frequency or by
computation. The zero-beat is displayed on the 540B
internal oscilloscope. Typical difference-frequency
displays obtained are shown in figures 3-4 and 3-5.
1-4.
The visual dieplay of the difference frequency
between two signals permits reading microwave carrier frequencies to very close tolerance while the
signal is being amplitude- or frequency-modulated,
or when it contains troublesome e amounts of noise. It
also permits measuring the incidental frequency modulation in amplitude-modulated carriers, the residual
frequency modulation in cw signals and the center frequency and Iimits of deviation in frequency-modulated
signals. When the 540B is used in conjunction with an
external oscilloscope, the carrier frequency of rf
pulses can also be measured to high accuracy. Typical
beat-frequency displays of pulse-modulated carriers
are shown in figures 3-10 and 3-11.
1-5. ACCURACY OF MEASUREMENT. The stability
of the transfer oscillator and the precision with which
it can be adjusted are sufficient that the high accuracy
and resolution of the electronic counters used for readout are utilized over the entire frequency range. Accuracies up to 1 part per million may be expected with
cw signals that are very stable and noise-free. Few
radio-frequency (rf) signals are stable enough to be
measured with such accuracy. Thus, the instability
of the signal being measured is usually the greatest
accuracy-limiting factor.
1-6. When measuring pulsed signals, accuracy de-
pends to some extent on pulse length because measurement can take place only during the pulse. Typical
accuracy obtainable when measuring a stable, pulsed
carrier of 1000 mc is approximately 3 parts per million for a 10-microsecond pulse duration and 10 parts
per million for a 2. 5-microsecond pulse.
1-7. DESCRIPTION OF EQUIPMENT. The trans-
fer oscillator is a single-unit, cabinet-mounted in-
strument.
The electronic circuitry haa four main
groups which can be interconnected by front panel
jumpers for a variety of measurement applications.
The four groups are shown in the block diagram in
figure 1-2, and listed below:
a. Oscillator Section. An internal oscillator generates a frequency from 100 to 220 mc, which is continuously adjustable by front panel controls. This
frequency is applied to frequency mixers and to an
external frequency counter for accurate frequency
indication.
b. Frequency Mixers. There are two mixers, a
low frequency mixer for input signals from about 10
mc to 5 gc and a high frequency mixer for input sig-
nals from 1 gc to 12.4 gc. The oscillator output is
connected to the proper mixer through a front panel
jumper. The mixer generates harmonics of the oscil-
lator signal which beat with the input signal and pro-
duce low-frequency beat signals which constitute the
mixer output.
c. Amplifier-Oscilloscope Section The amplifier
amplifies the mixer output to display the beat frequency on the built-in oscilloscope. The amplified
mixer output is also available for display on an external oscilloscope.
With the mixer output being
displayed on the oscilloscope, the frequency of the
oscillator can be adjusted until one of its harmonica
produces a zero-beat indication. The zero-beat indi-
cation on the oscilloscope differs in shape as different
types of signals having varying amounts of modulation
or noise are measured.
d. Harmonic Generator. This separate harmonic
generator section may be used to produce higherorder harmonics of the oscillator frequency for external amplification and use.
1-8.
ACCESSORIES FURNISHED. The Model 540B
Transfer Oscillator includes as part of the equipment
a 6-inch coaxial cable jumper with type BNC connectors for use in programming connections between the
jacks on the front panel, and a 4-foot coaxial cable
with type BNC connectors for connecting the transfer
oscillator to the electronic counter.
1-9. DIFFERENCES IN INSTRUMENTS.
1-10. This manual applies directly to 540B Transfer
Oscillators having the serial-number prefix 234. The
manual with the following changes aleo applies to 540B
Transfer Oscillators having serial-prefix numbers
128, 046, 015, 008, and the earlier prefix 129 for
serials between 101 and 597.
00161-2
1-1
Section I
Table 1-1
Model 540B
Table 1-1. Specifications
GENERAL
Frequency Range: 10 mc to at least 12.4 gc
Type of Input Signal: CW, AM, FM, or pulse
Maximum Input: 100 mw
Accuracy: Depends on character of unknown sig-
nal, accuracy of comparison, and accuracy with
which fundamental is measured. See discussion
in text.
Auxiliary Equipment:
Model 524 Sertes Electronic Counter
Model 525B Frequency Converter Unit
Model 150A Oscilloscope (for pulse measure-
m ent)
OSCILLATOR
Fundamental Frequency Range: 100 mc to 220 mc
OSCILLOSCOPE
Frequency Range: 100 cps to 200 kc
Vertical Deflection Sensitivity: 5 mv rms per inch
Horizontal Sweep:
External, 1 volt per inch, 20 cps to 5 kc
Internal, power supply frequency with phase
control
MISCELLANEOUS
Dimensions:
Cabinet Mount: 20-3/4 in. wide, 12-1/2 in. high,
15-1/4 in. deep
Harmonic Frequency Range: Above 12.4 gc
Stability: Less than 0.002% change per minute after
30 minutes warmup
Dial: Six-inch diameter, calibrated in l-me in-
crements. Accuracy ± 1/2%
Vernier Dial:
Mechanical - approximately 9:1
Electrical -
approximately ± 125 parts/million
Output: Approximately 2 volts into 50 ohms. Ad-
justed for optimum crystal harmonic generation.
AMPLIFIER
Gain: Adjustable, 40 db maximum
Bandwidth: 100 cycles to 2 megacycles
High Frequency Control: 3-db point adjustable from
below 1 kc to above 2 mc
Low Frequency Control: 3-db point switched from
100 cycles to below 10 kc, then continuously adjustable to above 400 kc
Maximum Undistorted Output: 1 volt rms usable
signal across 1000-obm load
1-2
Weight: Cabinet Mount: 42 lb, shipping 53 lb
Rack Mount:
35 lb, shipping 50 lb
Power Supply: 115 or 230 volts ± 10%, 50 to 1000
cps, approximately 110 watts
bly, 3 ft of RG-58/U 50-ohm coaxial cable termi-
nated at each end with UG-88/U type BNC male
connectors
Accessories Available:
50-ohm coaxial cable terminated at one end with
a UG-21B/U type male connector and with a UG-
23 B/U type N female connector at the other. (For
use at frequencies below 4000- mc. )
50-ohm coaxial cable terminated at one end only
with a UG-88/U type N BNC male connector
ohm coaxial cable terminated at each end with
UG-21B/U type N male. connectors.
(For use
at frequencies; below 4000 mc. )
treated RG-9A/U 50-ohm coaxial cable terminated at each end with UG-21B/U type N male
connectors.
Each cable is tested and selected
for minimum vswr at frequencies above 4000 mc.
00161-2
Model 540B
Section I
Paragraph 1-11
Figure 1-2. Diagram of Panel Connections and Functional Groups
1-11. To adapt this manual to instruments with other
instrument serials, make changes as follows:
Instrument Serial No.
129-01577 to 128-02701
046-01191 to 046-01516
015-00698 to 015-01190
008-598 to 008-697
129-00101 to 128-00597
Change No.
1, 2
1, 2
1, 2, 3
1, 2, 3
1, 3, 4
1. S4. Delete slide switch from schematic diagram,
parts lists, table 3-1. Refer to paragraph 2-9 for
details.
Q1, R76, R77, C49. Delete these parts from sche-
matic diagram, parts lists, and replace with R2,
Resistor, fixed, composition, 1200 ohms ± 10%,
2. Gear, frequency drive, large driving; change stock
number in parts lists to G36-H.
Gear, frequency drive, large spring loading; change
stock number in parts lists to G24-G.
Window, frequency dial; change stock number in
parts lists to G99-H.
3.
L8. Delete choke from schematic diagram and
parts Mats. Replace with wire jumper connected
to junction of J13 and L5.
4.
Regulated B+ at Vll pins 3 and 6; change to +225
volts, Decrease by about 7% the values of all tube
socket voltages listed for all tubes except V6, V8,
V10, Vll, V12, and V13.
R12. Change value to 27,000 ohms,
0690-2731.
R17. Change value to 1800 ohms,
0687-1821.
C47. Change value to 470 pf,
0027,
Gear, frequency drive, large driving; change
stock No. in parts lists to 200AB-36B.
Gear, frequency drive, large spring loading; change
stock No. in parts lists to 200AB-36C.
00161-1
1-3/1-4
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